The disclosure of Japanese Patent Application Laid-Open No. 2000-209841 filed on Jul. 11, 2000 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
1. Field of the Invention
The invention relates to a turn-signal automatic cancellation apparatus for canceling a turn signal as soon as a vehicle has almost completed its turn.
2. Description of Related Art
A turn-signal automatic cancellation apparatus for vehicles is disclosed e.g. in Japanese Patent Application Laid-Open No. HEI 5-319169. This apparatus is provided with a control portion for generating a right-turn or left-turn signal by blinking a direction indicator lamp based on a signal from a direction selecting switch (turn signal switch), and with an angular speed sensor for detecting an angular speed of a vehicle. The control portion calculates a turning angle of the vehicle by integrating the angular speed detected by the angular speed sensor and automatically cancels the turn signal generated from the direction indicator lamp on the condition that the turning angle be greater than a reference turning angle and that the angular speed detected by the angular speed sensor be lower than a reference angular speed.
In the above construction, however, if the vehicle has come to a halt at the center of an intersection to allow the passage of oncoming vehicles while attempting to make a right turn, i.e., has been waiting to make a right turn, the turning of the vehicle has been made by half by this moment with its turning angle greater than the reference turning angle and with its angular speed equal to zero (which is lower than the reference angular speed) due to a halt of the vehicle. Therefore, the vehicle suffers an inconvenience of unnecessary cancellation of a turn signal while being at a halt at the center of the intersection.
By the same token, if the vehicle has come to a halt to allow pedestrians to walk across a crosswalk while attempting to make a left turn, i.e., has been waiting to make a left turn, the turning of the vehicle has been made by half by this moment with its turning angle greater than the reference turning angle and with its angular speed equal to zero (which is lower than the reference angular speed) due to a halt of the vehicle. Therefore, the vehicle suffers an inconvenience of unnecessary cancellation of a turn signal while making a left turn.
It is an object of the invention to provide a turn-signal automatic cancellation apparatus capable of preventing a turn signal indicative of a turning direction of a vehicle from being canceled unnecessarily.
A turn-signal automatic cancellation apparatus according to one aspect of the invention comprises a controller for generating a turn signal from a direction indicator lamp based on a direction indicating signal from a turn signal switch, an angular speed sensor for detecting an angular speed of a vehicle, and a vehicle speed sensor for detecting a speed of the vehicle. The controller calculates a turning angle of the vehicle from the angular speed detected by the angular speed sensor and cancels the turn signal generated from the direction indicator lamp on the condition that the calculated turning angle be equal to or greater than a reference turning angle, that the vehicle speed detected by the vehicle speed sensor be equal to or higher than a reference vehicle speed, and that the angular speed detected by the angular speed sensor be equal to or lower than a reference angular speed.
According to such a construction, the turn signal is canceled on condition that the turning angle of the vehicle be equal to or greater than the reference turning angle, that the vehicle speed detected by the vehicle speed sensor be equal to or higher than the reference vehicle speed, and that the angular speed detected by the angular speed sensor be equal to or lower than the reference angular speed. Therefore, even if the turning angle of the vehicle is equal to or greater than the reference turning angle and the angular speed detected by the angular speed sensor is equal to or lower than the reference angular speed while the vehicle is waiting to make a right or left turn, the vehicle speed detected by the vehicle speed sensor does not become equal to or higher than the reference vehicle speed (the vehicle speed is actually zero). Thus, the turn signal is prevented from being canceled unnecessarily.
In the above aspect of the invention, the controller may calculate a-turning angle if the angular speed detected by the angular speed sensor is equal to or higher than a set angular speed.
According to such a construction, the controller calculates a turning angle if the angular speed detected by the angular speed sensor is equal to or higher than the set angular speed. Thus, if the vehicle is about to make a right or left turn at an intersection after having passed a road making a gentle curve while generating a turn signal from the direction indicator lamp, the angular speed detected by the angular speed sensor during the passage of the vehicle along the gentle curve is not calculated as the turning angle of the vehicle. Therefore, the turn signal can be prevented from being canceled while making a right or left turn or from remaining uncanceled after completion of a right or left turn.